Apparatus and method for repair of underground conduits

ABSTRACT

Apparatus and method for repairing underground conduits, such as well casings, particularly for repairing internal casings of deep wells. More particularly, the invention relates to a filter-sleeve and a method of conduit repair using such sleeve, without complete removal of the conduit or casing and without abandoning the well.

This application is based upon U.S. Patent Application No. 60/541,938, filed on Feb. 6, 2004, the disclosure of which is hereby incorporated-by-reference thereto in its entirety and the priority of which is claimed under 35 USC § 119(e).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to repairs of underground conduits and, more particularly, repairs and linings of internal well casings. More particularly, the invention relates to such repairs and linings, utilizing a filter-sleeve, without complete removal of the casing or abandonment of the well.

2. Description of Background and Relevant Information

For the purpose of repairing an underground pipe, such as a well casing, it is commonly necessary to remove the casing or to abandon the well in favor of a new well in view of the limitations of known technology.

A damaged well casing allows soil fines to enter the well. This can cause severe damage to pumps and other equipment.

The state of the art of repairing well casings and other underground pipes and conduits remains in need of a convenient and effective method and apparatus for repairing and sealing underground conduits, pipes, and casings, including those with screen sections, without removing such conduits, pipes, and casings, including such repair consisting of a complete relining.

SUMMARY OF THE INVENTION

An object of the invention is to provide for the structural repair and sealing of damaged underground conduits and pipes, particularly well casings, including casings having screen sections, by means of the installation of an expandable sleeve, thus creating support for the structurally weakened conduit, pipe, or casing.

An additional object of the invention to provide for the repair of damaged screens and openings, which might be incorporated within a damaged conduit, with a filter that can prevent the ingress of fines and sand into such conduit.

A still further object of the invention is to provide a means of continuing repair and maintenance of clogged and damaged filters with a screen that can be installed and removed for the purpose of replacement or cleaning, as the need arises.

A still further object of the invention is to provide a means by which the service life of a well, or other underground conduit, can be extended.

A sleeve according to the invention, hereafter referred to as a filter-sleeve, includes an expandable perforated non-corrodible core, such as a stainless steel core, equipped with a locking mechanism. The choice of core material is determined by the chemical regime in the well.

The core of the sleeve, according to a particular embodiment of the invention, is surrounded by filter material. According an embodiment of the invention, O-rings or other types of soft, possibly elastic, support devices are positioned on the sleeve, which can press the filter tightly against the host pipe upon expansion and installation of the filter-sleeve, which can create the pressure needed to secure the sleeve in place.

Installation, according to the invention, can be accomplished by use of an inflatable plug as an installation tool. Once the sleeve is expanded by means of the plug and locked by a locking device or other type of fastener, the plug is removed.

Infiltrating water, upon installation of the filter-sleeve, can pass through the filter material and the perforated sleeve.

The filter-sleeve of the invention provides an internal repair method and apparatus, designed for rehabilitation of conduits, pipes, well casings, and screens. The filter-sleeve can be used to repair holes, cracks, corrosion and other damage.

BRIEF DESCRIPTION OF DRAWINGS

Other objects, features, and advantages of the invention will be become apparent from the description of preferred embodiments of the invention, when considered in light of the accompanying drawings, in which:

FIG. 1 is a schematic illustration, in longitudinal cross section, of a filter-sleeve according to the invention;

FIG. 2 is a schematic illustration of a filter-sleeve combined with an installation plug to bring the filter-sleeve to the repair site;

FIG. 3 is a schematic perspective view illustrating the filter-sleeve combined with an installation plug, CCTV camera, and weight, being lowered into a damaged pipe;

FIG. 4 a is a schematic perspective view illustrating the filter-sleeve combined with an installation plug, placed over a damaged area;

FIG. 4 b is a schematic perspective view illustrating the filter-sleeve expanded by the installation plug and locked in place;

FIG. 5 a is a schematic perspective view illustrating the filter-sleeve installed, the installation plug with camera being lowered;

FIG. 5 b is a schematic view of the interior of the filter-sleeve showing a verification that the locks of the sleeve have been secured;

FIGS. 6 a, 6 b, and 6 c are schematic illustrations of the relative position between the filter-sleeve and the installation plug during different phases of the method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-6 schematically illustrate an exemplary apparatus according to the invention, as well as an exemplary manner by which such apparatus can be employed in making well repairs. However, the breadth of the invention is not intended to be limited by the particular illustrations and particular descriptions of such illustrations of the exemplary embodiments described herein, and is applicable to the repair of other types of conduits and pipes, particularly underground conduits and pipes.

FIG. 1 shows a filter-sleeve 1 according to the invention, in a schematic longitudinal cross section positioned within a well casing 9, or host pipe. As seen in FIG. 1, the well casing 9 has a damaged area 10, in the form of a hole, over which the filter-sleeve 1 is to be installed. Such damage can be created, for example, by electrolytic corrosion caused by the electrical current of a pump motor within the well/casing or a break caused by ground movements.

The filter-sleeve includes a core 2, that can be rolled from plain or corrugated sheet metal, such as stainless steel, plated or coated steel or plastic sheet, depending upon the chemical regime in the host casing/pipe 9.

The core 2 of the filter-sleeve 1, which can include a plurality of drain holes 6, is equipped with a locking arrangement, such as locks 8, or other types of fasteners, for locking the filter-sleeve according to any of a number of patents, in the name of the inventor of the instant invention, in the technology of no-dig repair, i.e., repair of underground pipes and conduits without excavation of the site of the repair. Among such patents, the disclosures of the following of which are hereby incorporated by reference thereto in their entireties, are U.S. Pat. No. 5,119,862, U.S. Pat. No. 5,351,720, and U.S. Pat. No. 6,138,718, which disclose methods and apparatus for making such repairs, using a repair sleeve that is transported to the location of damage of a host pipe, and fixed in place with an inflatable/expandable installation plug, the plug thereafter removed from the repair site.

The filter-sleeve 1 shown in FIG. 1 preferably includes a reinforcing coiled plate 3 equipped with drain holes. This optional plate can take the form of a second core made of stainless steel, for example, which is also perforated to allow water to penetrate.

The filter component of the filter-sleeve 1 shown in FIG. 1 is made from a suitable filtering material, such as felt 5, although such material could comprise a wire sieve, perforated sheet, or other porous material.

Further, the filter-sleeve 1 shown in FIG. 1 includes O-rings 4 or other type of support devices for the purpose of tightly fitting the filter-sleeve in the well casing 9, or host pipe, and for the purpose of supporting the filtering material.

The filter-sleeve 1 shown in FIG. 1 also includes an optional external protective netting or mesh 7, or other protective material.

Only as an exemplary embodiment of the invention, for a host pipe/well casing 9 having an internal diameter D_(hp) of 15.25 inches (38.74 mm), the body of the core 2 of the filter-sleeve shown in FIG. 1 has an outer diameter D_(sl), of approximately 14 inches (35.56 mm) and a length L of approximately 24 inches (60.96 mm). Obviously, however, the invention encompasses the lining and repair of pipes/casings of any size, the components of the filter-sleeves then being sized appropriately to accomplish the objectives consistent with the invention.

FIG. 2 is a schematic illustration of a filter-sleeve 1 coiled down upon and securely fitted onto an inflatable installation plug 11, thereby forming a sleeve/plug assembly which is then lowered into a well casing 9 that is in need of repair. For this purpose, the upper end 11 a of the plug 11 is connected to a coupling 12 via chains 13 or other attachment mechanism, thereby suspending the plug 11 by means of a cable, wire, or rope, for example, from an operational/monitoring station above ground.

The vertical alignment of the sleeve/plug assembly shown in FIG. 2 is adjusted by the weight 14 attached to the bottom of the plug 11. Also shown in FIG. 2 are a plurality of optional safety tapes 15, made of PVC, e.g., which are attached to the upper end of the plug 11 or to the chains 13 or cable supporting the sleeve/plug assembly, and to the interior of the filter-sleeve 1. The function of the safety tapes 15, if used, is explained below in connection with FIGS. 6 a, 6 b, and 6 c. In short, in the event the plug 11 were to lose its adherence to the filter-sleeve, the filter-sleeve can then retain its attachment to the plug 11 by being secured by the tapes 15 to the interior surface of the core of the filter-sleeve and to the top of the plug.

A band of tape 16, such as adhesive tape or other equivalent means, can be used to surround the entire assembly, at the bottom thereof as shown in FIG. 2, to assist in maintaining the various components of the filter-sleeve in place as the assembly is lowered into position.

An air hose 17 is fitted to the sleeve/plug assembly, as shown in FIG. 2, for use to inflate the expandable plug 11 as needed at the site of the repair in positioning the sleeve in place. Although air pressure is preferred for this purpose, water can be used for inflating the plug. Often, the free water surface in a well can be quite deep. Just by filling the hose the necessary installation pressure is created. The only complication using water for this purpose is providing for the release of the water after the installation is completed. This can be done, however, by using a valve, such as a pipe surrounding a sleeve that is part of the aforementioned hose. The sleeve would have a hole in it. During the installation, the pipe covers the hole. When the pressure must be released, the pipe is slid upwardly letting the water escape through the hole.

In FIG. 3, the filter-sleeve 1 and installation plug 11, forming the aforementioned sleeve/plug assembly, with weight 14, is shown being lowered into a damaged pipe 9, i.e., host casing. At the top of the assembly a CCTV camera 18 is positioned for use during the positioning of the assembly within the damaged pipe and for use during the repair.

FIG. 4 a schematically illustrates the sleeve/plug assembly having been lowered and positioned in place over the damaged area 10 of the pipe 9.

FIG. 4 b schematically illustrates the filter-sleeve 1 having been expanded, by means of the installation plug, according to methods taught by the inventor in any of the aforementioned patents, for example, to securely lock the filter-sleeve 1 in place within the pipe 9.

The protective mesh 7, if used, protects the felt 5, or other filtration material, during the expansion of the plug 11. In FIGS. 3, 4 a, 4 b, and 5 a, the circular ribbed outer surface of the filter-sleeve is the filter felt 5. The ribbed appearance results from the fact that the felt is soft and rests upon the aforementioned O-rings 4 shown in FIG. 1.

As the expansion of the plug causes the filter-sleeve 1 to reach the desired diameter, the locks 8 of the sleeve (or other locking device or fasteners) are caused to engage and thereby lock the filter-sleeve in a suitable expanded diameter, as is generally known in the art, such as disclosed in the aforementioned patents. The elasticity of the O-rings, upon deflation of the plug 11, effect the locking of the locks 8.

FIG. 5 a schematically illustrates the filter-sleeve 1 installed within the pipe and the installation plug 11, with camera 18, being lowered through the interior of the filter-sleeve 1, so that the proper engagement of the locks 8 thereof. FIG. 5 b illustrates the interior of the filter-sleeve, and a verification that the locks 8 along the length of the sleeve have been properly secured.

At the conclusion of the installation, following the aforementioned verification that the repair has been successfully completed, the installation plug and other accessories fitted with the plug are then raised and removed from the casing/pipe 9.

FIGS. 6 a, 6 b, and 6 c are schematic illustrations showing the relative position between the filter-sleeve and the installation plug during different phases of the method according to the invention. Also shown in these figures is a schematic depiction of the adhesive safety tapes 15, the use of which had been mentioned above as optional in connection with the creation of the filter-sleeve/installation plug assembly shown in FIG. 2.

For the sake of convenience in understanding, the host pipe 9 has been omitted from FIGS. 6 a, 6 b, and 6 c and reference numerals are not duplicated throughout these figures.

In FIG. 6 a, the filter-sleeve 1 and the installation plug 11 are shown in their combined position shown in FIG. 2. In FIG. 6 a, however, a plurality of adhesive safety tapes 15 are shown for ensuring that the filter-sleeve 1 does not slip off of the plug in the event, as mentioned above, the assembly were to be lowered deep within a well with sufficiently low temperatures that, for this or for another reason, the sleeve 1 were to lose its adherence to the plug. As shown in this optional feature of the invention, the plurality of tapes 15 are adhered to both the interior surface of the filter-sleeve 1 and to the plug 11. As can be seen in each of FIGS. 6 a, 6 b, and 6 c, the lower ends of the tapes 15 are fixed to the lower end of the plug 11. While the filter-sleeve 1 and installation plug 11 are positioned as shown in FIG. 6 a, of course, according to the description above, the assembly of filter-sleeve 1 and installation plug 11 is maintained as a unit by means of a slight expansion of the expandable/inflatable plug applying pressure from within the coiled sleeve 1.

After the filter-sleeve has been locked in place by the expansion of the inflatable plug 11 and the locking of the filter-sleeve against the well casing/pipe, as explained above, the deflated installation plug 11 is then lowered through the interior of the filter-sleeve 1, as shown in FIG. 6 b, for verifying the success of the repair by use of the CCTV camera as described above. This relative position of plug 11 and sleeve 1 shown in FIG. 6 b is also shown in FIG. 5 a, although in the latter figure the tapes 15 are not shown.

In FIG. 6 a, as the filter-sleeve/plug assembly is suspended by the cable 19 and before the filter-sleeve is locked in place against the inner surface of the casing, the filter-sleeve 1 is prevented from inadvertently falling downwardly relative to the plug by virtue of the attachment of the tapes 15. However, as shown in FIG. 6 b, the plug 11 itself is able to be lowered relative to the installed filter-sleeve 1 for the purpose of the verification step. The lower ends of the tapes 15, as shown in FIG. 6 b, provide sufficient slack for this.

Finally, as the installation plug 11 and other accessories fitted with the plug are raised from the casing/pipe, as shown in FIG. 6 c at the conclusion of the installation, the adhesive tapes 15 are peeled off of the inner surface of the installed filter-sleeve 1.

The filter-sleeve 1 of the invention forms a short single repair filter-sleeve in place. Alternatively, particularly in the case of a large damage area, or a damage area that extends along the casing/host pipe 9, a plurality of filter-sleeves can be successively installed to thereby form a multi-filter-sleeve repair inside the casing/host pipe.

After the filter-sleeve, or multi-filter-sleeve, is locked in place, the filter prevents fines and sand from entering the pipe and clean water passes through the felt, or other filtration material, and through the perforated sleeve into the pipe.

Over time, the fines and sand will clog the filter. The clogged filter can then be removed, cleaned for reuse, or replaced. 

1. A filter-sleeve for lining at least a portion of an underground conduit comprising: a perforated core coiled around a longitudinal axis adapted to be expanded within the underground conduit at a site of repair; and a filtering material surrounding the perforated core.
 2. A filter-sleeve according to claim 1, wherein the core comprises a rolled corrugated metal sheet.
 3. A filter-sleeve according to claim 1, wherein the core comprises a rolled plain metal sheet.
 4. A filter-sleeve according to claim 1, wherein the core comprises a rolled stainless steel sheet.
 5. A filter-sleeve according to claim 1, wherein the core comprises a coated steel or plastic sheet.
 6. A filter-sleeve according to claim 1, wherein the core is equipped with a locking device to facilitate locking of the core at the site of repair.
 7. A filter-sleeve according to claim 1, wherein the filtering material comprises felt, wire sieve, or a perforated sheet.
 8. A filter-sleeve according to claim 1, further comprising at least one O-ring surrounding the filtering material and for retaining the core in a coiled position for transporting the filter-sleeve to the site of repair.
 9. A filter-sleeve according to claim 1, further comprising an external protective material positioned over the filtering material.
 10. A filter-sleeve according to claim 1 in combination with an expandable installation plug, wherein the filter-sleeve is coiled around the installation plug and is securely affixed to the installation plug.
 11. A combination filter-sleeve/plug combination of claim 10, further comprising a plurality of adhesive tapes, each of the tapes having a first portion attached to an end portion of the installation plug and to an inner surface of the filter-sleeve.
 12. A method of lining a host casing using the filter-sleeve according to claim 1, the method comprising: coiling the core of the filter-sleeve on an inflatable installation plug to thereby produce a filter-sleeve/plug assembly; inserting the filter-sleeve/plug assembly into an underground host casing and positioning the assembly at a location to be lined with the filter-sleeve; expanding the inflatable installation plug to thereby expand the filter-sleeve and locking the filter-sleeve in place within the host casing.
 13. A method of lining a host casing according to claim 12, wherein the filter-sleeve includes O-ring(s), or other type of support device(s), surrounding the core for tightly fitting the filter-sleeve into the host casing and for supporting the filtering material.
 14. A method according to claim 12, further comprising deflating and removing the installation plug from the host casing.
 15. A method according to claim 14, wherein the filter-sleeve/plug assembly further comprises a plurality of adhesive tapes, each of the tapes having a first portion attached to an end portion of the installation plug, or to a portion of the assembly other than the filter-sleeve, and to an inner surface of the filter-sleeve, the method further comprising, after deflating the installation plug, raising the installation plug through the filter-sleeve and, during such raising, stripping the tapes from the inner surface of the filter-sleeve. 